Recent advances and improvements in communications technology provide the communications industry with enormous opportunities to improve existing services and to branch into new services. Thousands of miles of fiber optic cable have been deployed in optical networks. These optical networks make possible the transmission of large amounts of information at great speeds. Optical networks have been used primarily to carry voice signals in telecommunication applications. However, the advanced features of optical networks allow for the transmission of other information such as data, video and multimedia signals.
Although optical networks provide opportunities for the delivery of new and improved services, the cost of these services to subscribers remains high. The high cost stands as an impediment to the promulgation and acceptance of the new and improved services. One reason for the high cost is an inefficiency in the transport of information through optical networks. The inefficiency is discussed in further detail below in connection with a brief description of information transport facilities including optical networks.
To deliver information from one point to another, and especially to deliver data, video or multimedia signals from one point to another, service providers have used information transport facilities that include a combination of an asynchronous transfer mode (ATM) system and one or more optical networks. To function, information must be passed back and forth between the ATM system and any associated optical network. A particular method and system for the addition of information from an ATM switch to an optical network and for the dropping of information from an optical network to an ATM switch is described in the patent application filed on Feb. 15, 1996, assigned U.S. Ser. No. 08/601,962 and entitled: A Method and System for Interfacing an ATM Switch and an Optical Network. This referenced patent application (U.S. Ser. No. 08/601,962) is incorporated herein by reference. The inventor of the subject matter and the assignee of the referenced patent application (U.S. Ser. No. 08/601,962) are the same as in the present application.
A basic description of an information transport facility that includes an ATM system and an optical network is provided below.